In-the-ear (ITE) hearing devices are, at least in part, to be worn in a user's ear canal. Usually, the geometry of the user's ear canal is precisely measured, and thereupon a hard polymer casing for housing a transducer, a signal processor, a battery and the like is produced, which casing is, accordingly, individually shaped for the user's ear canal. Nevertheless, it happens that the casing gives rise to a sore in the ear canal, due to changes in cross-section of the ear canal.
It is known from the art to provide the hard casing of an ITE hearing device with a soft coating on the outside of the casing in order to prevent such sores.
It can be advantageous to have a rather tight fit of the hearing device in the ear canal, because this reduces the risk of feedback when a high amplification gain is used. A defined opening (“vent”) can provide for a defined air-penetrable connection between the inner part of the ear and the outside, which has a low risk of causing feedback. The vent equalizes pressure differences between the inside of the ear canal and the outside. The vent also suppresses the occurrence of low pressure (vacuum) in the inside of the ear canal when the hearing device is pulled out of the ear canal. Such a vacuum can occur when the ear canal is sealed by the hearing device and when the vent is plugged. This is unpleasant to the user, because the vacuum tends to pull the ear drum.
From DE 10 2004 010 866 A1, an insertion element is known, which can be connected to a behind-the-ear (BTE) hearing aid. The insertion element can support a supply line of the BTE hearing aid, which supply line can carry a signal from the BTE hearing device. The insertion element comprises a balloon, which can be filled, e.g., with a gas or a liquid, and emptied. The insertion element is inserted into a user's ear canal when the balloon is emptied. For filling the balloon, a syringe containing said gas or liquid can be connected via a tube to the balloon, and said gas or liquid can be filled into the balloon. The formerly small balloon will thereupon enlarge and adapts to the shape of the ear canal. It seems inconvenient to have to have a syringe or the like and the gas or liquid available whenever the insertion element shall be pumped up. Furthermore, it appears difficult, to properly adjust the pressure exerted on the inside of the ear canal by means of the syringe each time. In addition, it appears inconvenient to have to close the balloon (or tube) properly after filling it with the gas or liquid.